Catalyst composition for the production of olefin polymers

ABSTRACT

A catalyst composition comprising the reaction product of a) a monocycloalkadienyl catalyst precursor; b) an activity enhancing cycloalkadiene; and c) an activating cocatalyst is disclosed, which has high activity in the polymerization of olefins.

An improved catalyst composition and its use in the production of olefinpolymers are provided. The catalyst composition comprises the reactionproduct of a) a monocycloalkadienyl catalyst precursor, b) an activityenhancing cycloalkadiene; and c) an activating cocatalyst. The catalystcomposition demonstrates enhanced activity in the polymerization ofolefins.

BACKGROUND OF THE INVENTION

A variety of single site catalyst compositions have been developed toprepare olefin polymers. Single site catalysts have been shown to behighly useful in the preparation of polyolefins, producing relativelyhomogeneous copolymers at good polymerization rates, allowing one totailor closely the final properties of the polymer produced. In contrastto traditional Ziegler-Natta catalyst compositions, single site catalystcompositions comprise catalytic compounds in which each catalystcomposition molecule contains one or only a few polymerization sites.Metallocenes are the most well known type of single site catalystprecursor, and are organometallic coordination complexes containing oneor more pi-bonded moieties (i.e., cycloalkadienyl groups) in associationwith a metal atom from Groups IIIB to VIII or the Lanthanide series ofthe Periodic Table of Elements.

Monocycloalkadienyl catalyst precursors are useful single site catalystsprecursors. However, they sometimes demonstrate low activities inpolymerizing olefins. To this end, applicants have discovered that whenmonocycloalkadienyl catalyst precursors are combined with an activityenhancing cycloalkadiene and an activating cocatalyst, a catalystcomposition results having increased activity for the polymerization ofolefins relative to that of a catalyst composition containing only themonocycloalkadienyl catalyst precursor and activating cocatalyst. Inaddition, in certain instances, the properties of the olefin polymerproduced, such as its short chain branching frequency, are also improvedover that of an olefin polymer produced by a catalyst compositioncontaining only the monocycloalkadienyl catalyst precursor andactivating cocatalyst.

U.S. Pat. Nos. 5,387,567 and 5,451,555, and European Patent ApplicationPublication Nos. 0 546 690 A1, 0 587 440 A1, and 0 694 563 A1, allassigned to Nippon Oil Company, Ltd., relate to catalyst compositionscomprising transition metal compounds of the formula Me(OR)_(p) R_(q)X_(4-p-q) and MeR_(n) X_(4-n) wherein Me is a transition metal, each Ris a hydrocarbon group of 1-24 carbons, X is a halogen, and p, q, and nare each 0 to 4, and organocyclic compounds having two or moreconjugated double bonds. Such catalyst compositions may also includeGroup I-III metal compounds as well. However, the Nippon Oilpublications do not teach or suggest catalyst compositions that are thereaction product of a) a monocycloalkadienyl catalyst precursor, b) anactivity enhancing cycloalkadiene; and c) an activating cocatalyst, orthe increased activity of such catalyst compositions.

SUMMARY OF THE INVENTION

The invention provides a catalyst composition comprising the reactionproduct of:

a) monocycloalkadienyl catalyst precursor having the formula:

wherein:

M is a metal from groups IIIB to VIII or a rare earth metal of thePeriodic Table;

L is a cycloalkadienyl ligand;

each X is independently hydrogen, an aryl, alkyl, alkenyl, alkylaryl, orarylalkyl radical having 1-20 carbon atoms, a hydrocarboxy radicalhaving 1-20 carbon atoms, a halide, a nitrogen containing radical having1-20 carbon atoms, or Q₂ YZ, wherein each Q is independently selectedfrom the group consisting of --O--, --NR--, --CR₂ -- and --S--; Y iseither C or S; and Z is selected from the group consisting of --OR,--NR₂, --CR₃, --SR, --SiR₃, --PR₂, --H, and substituted or unsubstitutedaryl groups, with the proviso that when Q is --NR-- then Z is selectedfrom the group consisting of --OR, --NR₂, --SR, --SiR₃, --PR₂ and --H;and

x is 2, 3, or 4 depending upon the valence state of M;

b) an activity enhancing cycloalkadiene; and

c) an activating cocatalyst.

The invention also provides a process for the polymerization of anolefin, which comprises contacting at least one olefin monomer underpolymerization conditions with the above catalyst composition.

DETAILED DESCRIPTION OF THE INVENTION

Olefin polymers that may be produced according to the invention include,but are not limited to, ethylene homopolymers, homopolymers of linear orbranched higher alpha-olefins containing 3 to about 20 carbon atoms, andinterpolymers of ethylene and such higher alpha-olefins, with densitiesranging from about 0.86 to about 0.96. Suitable higher alpha-olefinsinclude, for example, propylene, 1-butene, 1-pentene, 1-hexene,4-methyl-1-pentene, 1-octene, and 3,5,5-trimethyl-1-hexene. Olefinpolymers according to the invention may also be based on or containconjugated or non-conjugated dienes, such as linear, branched, or cyclichydrocarbon dienes having from about 4 to about 20, preferably 4 to 12,carbon atoms. Preferred dienes include 1,4-pentadiene, 1,5-hexadiene,5-vinyl-2-norbornene, 1,7-octadiene, vinyl cyclohexene,dicyclopentadiene, butadiene, isobutylene, isoprene, ethylidenenorbornene, norbornadiene and the like. Aromatic compounds having vinylunsaturation such as styrene and substituted styrenes, and polar vinylmonomers such as acrylonitrile, maleic acid esters, vinyl acetate,acrylate esters, methacrylate esters, vinyl trialkyl silanes and thelike may be polymerized according to the invention as well. Specificolefin polymers that may be made according to the invention include, forexample, polyethylene, polypropylene, ethylene/propylene rubbers(EPR's), ethylene/propylene/diene terpolymers (EPDM's), polybutadiene,polyisoprene and the like.

The catalyst composition comprises the reaction product of: a) amonocycloalkadienyl catalyst precursor, b) an activity enhancingcycloalkadiene; and c) an activating cocatalyst. The monocycloalkadienylcatalyst precursor has the formula:

    LMX.sub.x                                                  (I)

wherein:

M is a metal from groups IIIB to VIII or a rare earth metal of thePeriodic Table;

L is cycloalkadienyl ligand, such as cyclopentadienyl, indenyl, orfluorenyl, optionally substituted with one or more hydrocarbyl groupscontaining 1 to 20 carbon atoms;

each X is independently hydrogen, an aryl, alkyl, alkenyl, alkylaryl, orarylalkyl radical having 1-20 carbon atoms, a hydrocarboxy radicalhaving 1-20 carbon atoms, a halide, a nitrogen containing radical having1-20 carbon atoms, or Q₂ YZ, wherein each Q is independently selectedfrom the group consisting of --O--, --NR--, --CR₂ -- and --S--,preferably oxygen; Y is either C or S, preferably carbon; and Z isselected from the group consisting of --OR, --NR₂, --CR₃, --SR, --SiR₃--, --PR₂, --H, and substituted or unsubstituted aryl groups, with theproviso that when Q is --NR-- then Z is selected from the groupconsisting of --OR, --NR₂, --SR, --SiR₃, --PR₂ and --H, preferably Z isselected from the group consisting of --OR, --CR₃ and --NR₂ ; and

x is 2, 3, or 4 depending upon the valence state of M.

Illustrative but non-limiting examples of catalyst precursorsrepresented by formula I are cyclopentadienyl titanium trichloride,methylcyclopentadienyl titanium trichloride, methylcyclopentadienyltitanium tribromide, pentamethylcyclopentadienyl titanium trichloride,indenyl titanium trichloride, cyclopentadienyl titanium trimethyl,cyclopentadienyl titanium triphenyl, cyclopentadienyl titaniumtris(methoxide), pentamethylcyclopentadienyl titanium tris(methoxide),cyclopentadienyl titanium tris(dimethylamide), cyclopentadienyl titaniumtris(diethylamide), cyclopentadienyl zirconium trichloride,methylcylopentadienyl zirconium trichloride, pentamethylcyclopentadienylzirconium trichloride, indenyl zirconium trichloride, cyclopentadienylzirconium tris(methoxide), methylcyclopentadienyl zirconiumtris(methoxide), pentamethylcyclopentadienyl zirconium tris(methoxide),indenyl zirconium tris(methoxide), cyclopentadienyl zirconium trimethyl,cyclopentadienyl zirconium trineopentyl, cyclopentadienyl zirconiumtrimethyl, cyclopentadienyl zirconium tris(dimethylamide),methylcyclopentadienyl zirconium tris (diethylamide), indenyl zirconiumtris(diethylamide); cyclopentadienyl hafnium trichloride,methylcyclopentadienyl hafnium trichloride, pentamethylcyclopentadienylhafnium trichloride, cyclopentadienyl hafnium triphenyl,cyclopentadienyl hafnium tri(neopentyl), cyclopentadienyl hafniumtrimethyl, cyclopentadienyl hafnium tris(methoxide), cyclopentadienylhafnium tris(diethylamide), and pentamethylcyclopentadienyl hafniumtris(diethylamide).

A preferred type of monocycloalkadienyl catalyst precursor for use inthe invention is a complex of a transition metal, a substituted orunsubstituted pi-bonded ligand, and one or more heteroallyl moieties,such as those described in U.S. Pat. No. 5,527,752. Preferably, suchcomplexes have one of the following formulas: ##STR1## wherein:

M is a transition metal, preferably Zr or Hf,

L is a substituted or unsubstituted, pi-bonded ligand coordinated to M,preferably a cycloalkadienyl ligand;

each Q is independently selected from the group consisting of --O--,--NR--, --CR₂ -- and --S--, preferably oxygen;

Y is either C or S, preferably carbon;

Z is selected from the group consisting of --OR, --NR₂, --CR₃, --SR,--SiR₃, --PR₂, --H, and substituted or unsubstituted aryl groups, withthe proviso that when Q is --NR-- then Z is selected from the groupconsisting of --OR, --NR₂, --SR, --SiR₃, --PR₂ and --H, preferably Z isselected from the group consisting of --OR, --CR₃ and --NR₂ ;

n is 1 or.2;

A is a univalent anionic group when n is 2 or A is a divalent anionicgroup when n is 1, preferably A is a carbamate, carboxylate, or otherheteroallyl moiety described by the Q, Y and Z combination; and

each R is independently a group containing carbon, silicon, nitrogen,oxygen, and/or phosphorus where one or more R groups may be attached tothe L substituent, preferably R is a hydrocarbon group containing from 1to 20 carbon atoms, most preferably an alkyl, cycloalkyl, or an arylgroup and one or more may be attached to the L substituent;

or ##STR2##

wherein:

M is a transition metal, preferably Zr or Hf;

L is a substituted or unsubstituted, pi-bonded ligand coordinated to M,preferably a cycloalkadienyl ligand;

each Q is independently selected from the group consisting of --O--,--NR--, --CR₂ and --S--, preferably oxygen;

Y is either C or S, preferably carbon;

Z is selected from the group consisting of --OR, --NR₂, --CR₃, --SR,--SiR₃, --PR₂, --H, and substituted or unsubstituted aryl groups, withthe proviso that when Q is --NR-- then Z is selected from the groupconsisting of --OR, --NR₂, --SR, --SiR₃, --PR₂ and --H, preferably Z isselected from the group consisting of --OR, --CR₃ and --NR₂ ;

n is 1 or 2;

A is a univalent anionic group when n is 2 or A is a divalent anionicgroup when n is 1, preferably A is a carbamate, carboxylate, or otherheteroallyl moiety described by the Q, Y and Z combination;

each R is independently a group containing carbon, silicon, nitrogen,oxygen, and/or phosphorus where one or more R groups may be attached tothe L substituent, preferably R is a hydrocarbon group containing from 1to 20 carbon atoms, most preferably an alkyl, cycloalkyl, or an arylgroup and one or more may be attached to the L substituent;

T is a bridging group selected from the group consisting of alkylene andarylene groups containing from 1 to 10 carbon atoms optionallysubstituted with carbon or heteroatoms, germanium, silicone and alkylphosphine; and

m is 2 to 7, preferably 2 to 6, most preferably 2 or 3.

In formulas I, II, and III, the substituent formed by Q, Y and Z is aunicharged polydentate ligand exerting electronic effects due to itshigh polarizability, similar to the cyclopentadienyl group. In the mostpreferred embodiments of this invention, the disubstituted carbamates,##STR3## and the carboxylates ##STR4## are employed.

Examples of complexes according to formulas II and III include indenylzirconium tris(diethylcarbamate), indenyl zirconiumtris(trimethylacetate), indenyl zirconium tris(p-toluate), indenylzirconium tris(benzoate), (1-methylindenyl)zirconium tris(pivalate),(2-methylindenyl) zirconium tris(diethylcarbamate),(methylcyclopentadienyl) zirconium tris(trimethylacetate),cyclopentadienyl tris(pivalate), and (pentamethylcyclopentadienyl)zirconium tris(benzoate). Preferred examples are indenyl zirconiumtris(diethylcarbamate), indenyl zirconium tris(trimethylacetate), and(methylcyclopentadienyl) zirconium tris(trimethylacetate).

The catalyst precursor may be made by any means, and the invention isnot limited thereby. For example, a method of manufacturing a preferredcatalyst precursor, indenyl zirconium tris(diethylcarbamate), is firstto react a source of cycloalkadienyl ligand with a metal compound of theformula M(NR₂)₄, in which M and R are defined above, to introduce thecycloalkadienyl ligand onto the metal compound. The resulting product isthen dissolved in an inert solvent, such as toluene, and theheterocumulene CO₂ is contacted with the dissolved product to insertinto one or more M--NR₂ bonds to form a carbamate.

The activity enhancing cycloalkadiene is an organocyclic compound havingtwo or more conjugated double bonds, examples of which include cyclichydrocarbon compounds having two or more, preferably 2-4, morepreferably 2-3, conjugated double bonds and 4-24, preferably 4-12,carbons, optionally substituted with a substituting group such as alkylor aralkyl of 1-12 carbon atoms.

Examples of activity enhancing cycloalkadienes include unsubstituted andsubstituted cyclopentadienes, indenes, fluorenes, and fulvenes, such ascyclopentadiene, methylcyclopentadiene, ethylcyclopentadiene,t-butylcyclopentadiene, hexylcyclopentadiene, octylcyclopentadiene,1,2-dimethylcyclopentadiene, 1,3-dimethylcyclopentadiene,1,2,4-trimethylcyclopentadiene, 1,2,3,4-tetramethylcyclopentadiene,pentamethylcyclopentadiene, indene, 4-methyl-1-indene,4,7-dimethylindene, 4,5,6,7-tetrahydroindene, fluorene, methylfluorene,cycloheptatriene, methylcycloheptatriene, cyclooctatraene,methylcyclooctatraene, fulvene and dimethylfulvene. These compounds maybe bonded through an alkylene group of 2-8, preferably 2-3, carbonatoms, such as for example bis-indenylethane,bis(4,5,6,7-tetrahydro-1-indenyl)ethane,1,3-propanedinyl-bis(4,5,6,7-tetrahydro)indene, propylene-bis(1-indene),isopropyl(1-indenyl) cyclopentadiene, diphenylmethylene(9-fluorenyl),cyclopentadiene and isopropylcyclopentadienyl-1-fluorene. Preferably,the activity enhancing cycloalkadiene is selected from the groupconsisting of cyclopentadiene, methylcyclopentadiene, indene, andmethyl-n-propylcyclopentadiene.

The amount of activity enhancing cycloalkadiene used is about 0.01 toabout 10 moles per mole of catalyst precursor. Preferably, about 0.1 toabout 2.0 moles of cycloalkadiene per mole of catalyst precursor areused. More preferably, about 0.2 to about 1.0 moles of cycloalkadieneper mole of catalyst precursor are used.

In one embodiment of the invention, the amount of cycloalkadiene used isabout 0.1 to about 2.0 moles per mole of catalyst precursor, preferablyabout 0.1 to about 1.1 moles per mole of catalyst precursor. Under theseconditions, a 0.920 density ethylene polymer may be made having one ormore of the following properties: a high number average molecularweight, i.e., in the range of about 5000 to about 200,000, preferablyabout 20,000 to about 100,000, a narrow molecular weight distribution(PDI), i.e., about 3 to 5, or a high short chain branch frequency, i.e.,at least about 10 short chain branches per 1000 main chain carbons,preferably at least about 15 short chain branches per main chaincarbons, as measured by carbon-13 MNR.

The activating cocatalyst is capable of activating the catalystprecursor. Preferably, the activating cocatalyst is one of thefollowing: (a) branched or cyclic oligomeric poly(hydrocarbylaluminumoxide)s which contain repeating units of the general formula--(Al(R^(*))O)--, where R^(*) is hydrogen, an alkyl radical containingfrom 1 to about 12 carbon atoms, or an aryl radical such as asubstituted or unsubstituted phenyl or naphthyl group; (b) ionic saltsof the general formula A⁺ ! BR^(**) ₄ --!, where A⁺ is a cationic Lewisor Bronsted acid capable of abstracting an alkyl, halogen, or hydrogenfrom the metallocene catalysts, B is boron, and R^(**) is a substitutedaromatic hydrocarbon, preferably a perfluorophenyl radical; (c) boronalkyls of the general formula BR^(**) ₃, where R^(**) is as definedabove; or mixtures thereof.

Preferably, the activating cocatalyst is a branched or cyclic oligomericpoly(hydrocarbylaluminum oxide) or a boron alkyl. More preferably, theactivating cocatalyst is an aluminoxane such as methylaluminoxane (MAO)or modified methylaluminoxane (MMAO), or a boron alkyl.

Aluminoxanes are well known in the art and comprise oligomeric linearalkyl aluminoxanes represented by the formula: ##STR5## and oligomericcyclic alkyl aluminoxanes of the formula: ##STR6## wherein s is 1-40,preferably 10-20; p is 3-40, preferably 3-20; and R^(***) is an alkylgroup containing 1 to 12 carbon atoms, preferably methyl.

Aluminoxanes may be prepared in a variety of ways. Generally, a mixtureof linear and cyclic aluminoxanes is obtained in the preparation ofaluminoxanes from, for example, trimethylaluminum and water. Forexample, an aluminum alkyl may be treated with water in the form of amoist solvent. Alternatively, an aluminum alkyl, such astrimethylaluminum, may be contacted with a hydrated salt, such ashydrated ferrous sulfate. The latter method comprises treating a dilutesolution of trimethylaluminum in, for example, toluene with a suspensionof ferrous sulfate heptahydrate. It is also possible to formmethylaluminoxanes by the reaction of a tetraalkyldialuminoxanecontaining C₂ or higher alkyl groups with an amount of trimethylaluminumthat is less than a stoichiometric excess. The synthesis ofmethylaluminoxanes may also be achieved by the reaction of a trialkylaluminum compound or a tetraalkyldialuminoxane containing C₂ or higheralkyl groups with water to form a polyalkyl aluminoxane, which is thenreacted with trimethylaluminum. Further modified methylaluminoxanes,which contain both methyl groups and higher alkyl groups, i.e., isobutylgroups, may be synthesized by the reaction of a polyalkyl aluminoxanecontaining C₂ or higher alkyl groups with trimethylaluminum and thenwith water as disclosed in, for example, U.S. Pat. No. 5,041,584.

When the activating cocatalyst is a branched or cyclic oligomericpoly(hydrocarbylaluminum oxide), the mole ratio of aluminum atomscontained in the poly(hydrocarbylaluminum oxide) to total metal atomscontained in the catalyst precursor is generally in the range of fromabout 2:1 to about 100,000:1, preferably in the range of from about 10:1to about 10,000:1, and most preferably in the range of from about 50:1to about 2,000:1. When the activating cocatalyst is an ionic salt of theformula A⁺ ! BR^(**) ₄ --! or a boron alkyl of the formula BR^(**) ₃,the mole ratio of boron atoms contained in the ionic salt or the boronalkyl to total metal atoms contained in the catalyst precursor isgenerally in the range of from about 0.5:1 to about 10:1, preferably inthe range of from about 1:1 to about 5:1.

The catalyst composition may be impregnated onto a solid, inert support,in liquid form such as a solution or dispersion, spray dried, in theform of a prepolymer, or formed in-situ during polymerization.Particularly preferred among these is a catalyst composition that isspray dried as described in European Patent Application No. 0 668 295 A1or in liquid form as described in U.S. Pat. No. 5,317,036.

In the case of a supported catalyst composition, the catalystcomposition may be impregnated in or deposited on the surface of aninert substrate such as silica, carbon black, polyethylene,polycarbonate porous crosslinked polystyrene, porous crosslinkedpolypropylene, alumina, thoria, zirconia, or magnesium halide (e.g.,magnesium dichloride), such that the catalyst composition is between 0.1and 90 percent by weight of the total weight of the catalyst compositionand the support.

The catalyst composition may be used for the polymerization of olefinsby any suspension, solution, slurry, or gas phase process, using knownequipment and reaction conditions, and is not limited to any specifictype of reaction system. Generally, olefin polymerization temperaturesrange from about 0° C. to about 200° C. at atmospheric, subatmospheric,or superatmospheric pressures. Slurry or solution polymerizationprocesses may utilize subatmospheric or superatmospheric pressures andtemperatures in the range of about 40° C. to about 110° C. A usefulliquid phase polymerization reaction system is described in U.S. Pat.No. 3,324,095. Liquid phase reaction systems generally comprise areactor vessel to which olefin monomer and catalyst composition areadded, and which contains a liquid reaction medium for dissolving orsuspending the polyolefin. The liquid reaction medium may consist of thebulk liquid monomer or an inert liquid hydrocarbon that is nonreactiveunder the polymerization conditions employed. Although such an inertliquid hydrocarbon need not function as a solvent for the catalystcomposition or the polymer obtained by the process, it usually serves assolvent for the monomers employed in the polymerization. Among the inertliquid hydrocarbons suitable for this purpose are isopentane, hexane,cyclohexane, heptane, benzene, toluene, and the like. Reactive contactbetween the olefin monomer and the catalyst composition should bemaintained by constant stirring or agitation. The reaction mediumcontaining the olefin polymer product and unreacted olefin monomer iswithdrawn from the reactor continuously. The olefin polymer product isseparated, and the unreacted olefin monomer and liquid reaction mediumare recycled into the reactor.

Preferably, gas phase polymerization is employed, with superatmosphericpressures in the range of 1 to 1000 psi, preferably 50 to 400 psi, mostpreferably 100 to 300 psi, and temperatures in the range of 30° to 130°C., preferably 65° to 110° C. Stirred or fluidized bed gas phasereaction systems are particularly useful. Generally, a conventional gasphase, fluidized bed process is conducted by passing a stream containingone or more olefin monomers continuously through a fluidized bed reactorunder reaction conditions and in the presence of catalyst composition ata velocity sufficient to maintain a bed of solid particles in asuspended condition. A stream containing unreacted monomer is withdrawnfrom the reactor continuously, compressed, cooled, optionally fully orpartially condensed as disclosed in U.S. Pat. Nos. 4,528,790 and5,462,999, and recycled to the reactor. Product is withdrawn from thereactor and make-up monomer is added to the recycle stream. As desiredfor temperature control of the system, any gas inert to the catalystcomposition and reactants may also be present in the gas stream. Inaddition, a fluidization aid such as carbon black, silica, clay, or talcmay be used, as disclosed in U.S. Pat. No. 4,994,534.

Polymerization may be carried out in a single reactor or in two or morereactors in series, and is conducted substantially in the absence ofcatalyst poisons. Organometallic compounds may be employed as scavengingagents for poisons to increase the catalyst activity. Examples ofscavenging agents are metal alkyls, preferably aluminum alkyls, mostpreferably triisobutylaluminum.

Conventional adjuvants may be included in the process, provided they donot interfere with the operation of the catalyst composition in formingthe desired polyolefin. Hydrogen or a metal or non-metal hydride, e.g.,a silyl hydride, may be used as a chain transfer agent in the process.Hydrogen may be used in amounts up to about 10 moles of hydrogen permole of total monomer feed.

The following examples further illustrate the invention.

EXAMPLES

Glossary

Activity is measured in g polyethylene/mmol metal hr 100 psi ethylene.

MAO is a solution of methylaluminoxane in toluene, approximately 2.0molar in aluminum, commercially available from Akzo Chemicals, Inc.

MMAO is a solution of modified methylaluminoxane in hexane,approximately 2.25 molar in aluminum, commercially available from AkzoChemicals, Inc. (type M).

Density in g/cc is determined in accordance with ASTM 1505, based onASTM D-1928, procedure C, plaque preparation. A plaque is made andconditioned for one hour at 100° C. to approach equilibriumcrystallinity, measurement for density is then made in a densitygradient column.

TIBA is triisobutylaluminum.

MI is melt index, reported as grams per 10 minutes, determined inaccordance with ASTM D-1238, condition E, at 190° C.

FI is flow index, reported as grams per 10 minutes, is determined inaccordance with ASTM D-1238, condition F, and is measured at ten timesthe weight used in the melt index text.

MFR is melt flow ratio, which is the ratio of flow index to melt index.It is related to the molecular weight distribution of the polymer.

BBF

BBF is butyl branch frequency as determined using carbon-13 NMR. An 8%weight/volume concentration was prepared by dissolving an ethylenecopolymer in ortho dichlorobenzene (ODCB) in an NMR tube. A closedcapillary tube of deuterium oxide was inserted into the NMR tube as afield frequency lock. Data was collected on the Bruker AC 300 at 115° C.using NOE enhanced conditions with a 30° PW and a 5 second repetitiontime. The number of carbon scans usually varied from 1,000 to 10,000with the more highly branched samples requiring shorter acquisitions.The area of the peaks was measured along with the area of the totalaliphatic region. The areas of carbons contributed by the comonomer wereaveraged and ratioed to the area of the backbone to give the molefraction. This number was then converted into branch frequency.

Determination of Zr in Polyethylene

Polyethylene samples were weighed into platinum crucibles, ignited, thenplaced in a muffle furnace (580° C.) until all the carbon had burnedoff. After cooling, hydrochloric acid was added to the residue and itwas heated gently to aid dissolution. The crucibles were cooled, andhydrofluoric acid was added to insure total dissolution of the silicane.The samples were then quantitatively transferred and diluted to 15 mlwith deionized water and analyzed using an Inductively-Coupled Plasma(Atom Scan 25, Thermo Jarrell Ash).

Catalyst Precursor Preparations: η⁵ --IndZr(O₂ CNE_(t2))₃ and η⁵--MeIndZr (O₂ C(CH)₃ !₃

First, η⁵ --IndZr(NEt₂)₃ was prepared by reacting indene (in excess)with Zr(NEt₂)₄ either neat or in toluene solution at 100°-115° for 1-4hours. The resulting Et₂ NH, along with the toluene, was pumped off andthe excess indene removed under high vacuum (110°/0.05 mmHg/0.5 hr).This yielded an approx. 95 mole % pure η⁵ --IndZr(NEt₂)₃ residueproduct. All analyses were by ¹ H-NMR using d₈ -toluene as solvent andNMR lock.

Next, an approx. 2 wt. % solution of the η⁵ --IndZr(NEt₂)₃ residueproduct in toluene (dried over CaH₂) was placed in a small Hoke cylinder(25-100 ml). The solution in the Hoke cylinder (under N₂) was cooled toapprox. 0° C. in an ice bath. Carbon dioxide (HPLC grade) was addedthereto, first at low pressure (1-5 psi) with good agitation, and thenat increased pressure (60 psi) for 0.5 hr. Thus, a dilute toluenesolution of η⁵ -indenyl zirconium tris(diethylcarbamate) was obtained,which contained 3-7 mole % of free indene. This was stored at r.t. in a<1 ppm O₂ /H₂ O drybox in a Teflon coated, crimped topped bottle.

η⁵ -Methycyclopentadienyl zirconium tris(diethylamide) was prepared by asimilar procedure. This, in dilute toluene solution, at -50° to -75°,was reacted with a toluene solution of pivalic acid (trimethyl aceticacid) resulting in the η⁵ -methylcyclopentadienyl zirconiumtris(trimethylacetate). This was purified by recrystallization fromaliphatic hydrocarbons at low temperatures.

All reactions and manipulation s were carried out in a <1 ppm O₂ /H₂ Odrybox or on a vacuum line. Exceptional care was taken to exclude H₂ O,O₂ and polar compounds.

Catalyst Precursor Preparation: CpZrCl₃

CPZrCl₃ is commercially available from Strem Chemicals, and may also besynthesized according to Reid et al., J. Organomet. Chem., Vol. 2, p.329 (1964).

EXAMPLES 1-24

A series of ethylene/1-hexene copolymers were produced in a 1.8 liter,stirred (275 rpm), slurry phase reactor using η⁵ -indenyl zirconiumtris(diethylcarbamate)/MMAO catalyst compositions. In Example 1, thecatalyst composition comprised only η⁵ -indenyl zirconiumtris(diethylcarbamate) and MMAO. In Examples 2-24, the catalystcompositions comprised η⁵ -indenyl zirconium tris(diethylcarbamate),MMAO and an activity enhancing cycloalkadiene as shown in Table 1.Examples 1-24 were carried out as follows.

The reactor was baked out (110° C./N₂) for approx. 1 hr. After cooling,1,000 ml of deoxygenated hexanes were added along with 100 ml of freshlydistilled (over CaH₂) 1-hexene and 1.14 ml TIBA (in heptanes, 0.87mmole, equal to 1 mmole). The reactor was closed, brought to temperature(85° C.), 100 ml H₂ was added, and the reactor was pressured to 200 psitotal system pressure with ethylene. At pressure equilibrium, onemicromole of catalyst composition solution containing η⁵ -indenylzirconium tris(diethylcarbamate), MMAO, and optionally cycloalkadienewas injected through a high pressure septum/pressure syringe. Thecycloalkadiene was added to the catalyst composition such that eachcatalyst precursor molecule was paired with one cycloalkadiene ring.Thus, when the cycloalkadiene had two rings, the mole ratio ofcycloalkadiene to catalyst precursor was 0.5.

This initiated the reaction. Very active catalyst compositions typicallyresulted in temperature increases to 90°-95° C., soon brought undercontrol to level out at 85° C.±2° C. The ethylene flow rate, systempressure, and reactor temperature (internal and external) was monitoredcontinuously. The reactions were run for 30 min., unless the catalystcomposition proved to be too productive. In this case, the reactionswere run for only 10-15 min. (no more than approx. 900 counts approx. 90g polymer). Polymerization was terminated by injection of 1 ml anhydrousisopropanol (at temperature and pressure), and simultaneouscooling/venting. Thus, the polymerization reaction was initiated andterminated under the stated temperature and pressure conditions.

After discharging the reactor the polymer/hexane slurry was mixed with0.35 g IRGANOX in 1 ml acetone (stabilizer). The entire polymer slurrywas evaporated to dryness overnight under a well ventilated hood. Thedried polymer was weighed and analyzed for Zr contents.

The results of Examples 1-24 are shown in Table 1.

EXAMPLES 25-29

A series of ethylene/1-hexene copolymers were produced in the samemanner as Examples 1-24 using an η⁵ -indenyl zirconiumtris(diethylcarbamate)/MMAO catalyst composition containing varyingamounts of cyclopentadiene. The results are shown in Table II.

EXAMPLES 30-37

A series of ethylene/1-hexene copolymers were produced in the samemanner as Examples 1-24 using η⁵ -methylcyclopentadienyl zirconiumtris(trimethylacetate)/MMAO catalyst compositions instead. In Example30, the catalyst composition comprised only η⁵ -methylcyclopentadienylzirconium tris(trimethylacetate) and MMAO. In Examples 31-37, thecatalyst compositions comprised η⁵ -methylcyclopentadienyl zirconiumtris(trimethylacetate), MMAO, and an activity enhancing cycloalkadiene.

The results are shown in Table III.

EXAMPLES 38 AND 39

Two ethylene/1-hexene copolymers were produced in a mechanicallystirred, pilot scale, gas phase reactor. In Example 38, the catalystcomposition comprised only η⁵ -indenyl zirconium tris(diethylcarbamate)and MMAO. In Example 39, the catalyst composition comprised η⁵ -indenylzirconium tris(diethylcarbamate), MMAO, and cyclopentadiene. Examples 38and 39 were carried out as follows.

Before both batch runs, a pre-bed was charged to the reactor, which wasthen pressure-purged with nitrogen three times to 100 psig. Jackettemperature was adjusted to hold the material at approximately 80° C.overnight while under a 3-4 lb./hr nitrogen flow purge at 100 psigreactor pressure. Prior to both runs, the reactor was pressure purgedonce to 300 psi and then 50 ml of cocatalyst solution were then chargedto further passivate the reactor. The reactor was then pressure purgedfour more times to 100 psig. Raw materials were charged to establish theinitial gas phase concentrations of ethylene, hexene, and nitrogen.Gas-phase concentrations are normally held near these initial valuesthroughout the batch.

Catalyst composition was fed to the reactor continuously during thepolymerization using isopentane as a carrier and nitrogen as adispersant. Catalyst feed rate was adjusted as required to maintainpolymerization rates of 5-7 lbs/hr.

Monomers and hydrogen were fed continuously as required to maintain gasphase composition throughout the batch. The 1-hexene/ethylene mole ratiowas maintained in the range of 0.034 to 0.036. A small vent stream wasused to prevent accumulation of the nitrogen added with the catalyst.The batch was terminated when the bed weight approached 25-30 lbs. byshutting off the feeds and rapidly venting the reactor to atmosphericpressure. The reactor was then pressure purged five times to 100 psiwith dry nitrogen. The resin was then discharged into a product box andexposed to the atmosphere. Once in the box, a two-nozzle purgingmanifold was inserted deep into the resin in order to purge it out withwater-saturated nitrogen overnight at ambient temperature.

The results are shown in Table IV.

EXAMPLES 40-48

A series of ethylene/1-hexene copolymers were produced in a 1.0 liter,stirred (190 rpm), slurry phase reactor using cyclopentadienyl zirconiumtrichloride/MAO catalyst compositions. In Example 48, the catalystcomposition comprised only cyclopentadienyl zirconium trichloride andMAO. In Examples 40-47, the catalyst compositions comprisedcyclopentadienyl zirconium trichloride, MAO and an activity enhancingcycloalkadiene as shown in Table V. Examples 40-48 were carried out asfollows.

The reactor was baked out (110° C./N₂) for approx. 1 hr. After cooling,500 ml of deoxygenated hexanes were added along with 0 to 40 ml offreshly distilled (over CaH₂) 1-hexene and 0.5 to 1.0 ml TIBA (inheptanes, 0.87 mmole). The reactor was closed, brought to temperature(85° C.), and the reactor was pressured to 150 psi total system pressurewith ethylene. At pressure equilibrium, a suitable amount of catalystcomposition solution (formed by combining cyclopentadienyl zirconiumtrichloride, MAO cocatalyst in toluene solution, and an activityenhancing cycloalkadienyl, aged for a measured period of time) wasintroduced into the reactor in the amount shown in Table V.

The reactions were run for 30 minutes, except in the case of Example 40,which was run for 15 minutes. Polymerization was terminated by injectionof 1 ml anhydrous isopropanol (at temperature and pressure), andsimultaneous cooling/venting. After discharging the reactor thepolymer/hexane slurry was evaporated to dryness overnight under a wellventilated hood.

The results of Examples 40-48 are shown in Table V.

EXAMPLES 49-54

A series of 0.920 density ethylene/1-hexene copolymers were produced inpilot scale, fluidized bed, gas phase reactor. In Examples 49 and 50,the catalyst composition comprised only η⁵ -methylcyclopentadienylzirconium tris(trimethylacetate) and MMAO. In Examples 51-54, thecatalyst compositions comprised η⁵ -methylcyclopentadienyl zirconiumtris(trimethylacetate) and methyl n-propyl cyclopentadiene in a 1:1 moleratio and MMAO.

Catalyst composition was fed to the reactor continuously during thepolymerization using an isopentane/1-hexene mix as a carrier andnitrogen as a dispersant. Monomers and hydrogen were fed continuously asrequired to maintain gas phase composition. The 1-hexene/ethylene moleratio was maintained in the range of 0.027 to 0.032. In Example 53,polymerization was conducted in condensing mode, with 6 weight percentcondensed isopentane in the polymerization zone. In Example 54,polymerization was conducted in condensing mode, with 7 weight percentcondensed isopentane in the polymerization zone.

The results are shown in Table VI.

                                      TABLE I                                     __________________________________________________________________________    Example                                                                            Cycloalkadiene       Activity                                                                          MI FI MFR                                                                              BBF                                    __________________________________________________________________________     1   None                 22,700                                                                            13.9     5.8                                     2                                                                                  ##STR7##            79,900                                                                            6.4                                                                              -- -- 8.4                                     3                                                                                  ##STR8##            98,800                                                                            8.7                                                                              -- -- 15.2                                    4                                                                                  ##STR9##            82,600                                                                            6.52                                                                             -- -- 11.7                                    5                                                                                  ##STR10##           60,000                                                                            3.35                                                                             97.9                                                                             29.2                                                                             11.7                                    6                                                                                  ##STR11##           39,500                                                                            20.8                                                                             -- -- 7.0                                     7                                                                                  ##STR12##           90,800                                                                            8.1                                                                              -- -- 9.3                                     8                                                                                  ##STR13##           82,700                                                                            1.6                                                                              32.7                                                                             24.2                                                                             7.4                                     9                                                                                  ##STR14##           70,000                                                                            2.1                                                                              51.0                                                                             24.3                                                                             8.3                                    10                                                                                  ##STR15##           91,200                                                                            12.5                                                                             -- -- 11.7                                   11                                                                                  ##STR16##           50,600                                                                            1.19                                                                             -- -- 7.3                                    12                                                                                  ##STR17##           45,400                                                                            0.81                                                                             39.8                                                                             32.2                                                                             6.9                                    13                                                                                  ##STR18##           76,100                                                                            4.9                                                                              -- -- 11.8                                   14                                                                                  ##STR19##           36,400                                                                            1.53                                                                             -- -- 8.4                                    15                                                                                  ##STR20##           32,500                                                                            0.89                                                                             32.4                                                                             28.8                                                                             8.2                                    16                                                                                  ##STR21##           17,800                                                                            15.0                                                                             -- -- 6.0                                    17                                                                                  ##STR22##           14,200                                                                            5.8                                                                              -- -- 6.0                                    18                                                                                  ##STR23##            9,850                                                                            0.81                                                                             53.1                                                                             43.0                                                                             7.8                                    19                                                                                  ##STR24##           60,800                                                                            0.77                                                                             30.5                                                                             23.5                                                                             7.9                                    20                                                                                  ##STR25##           91,200                                                                            1.17                                                                             25.6                                                                             22.0                                                                             9.2                                    21                                                                                  ##STR26##           65,900                                                                            6.1                                                                              -- -- 10.8                                   22                                                                                  ##STR27##           60,700                                                                            0.51                                                                             50.6                                                                             25.8                                                                             4.2                                    23                                                                                  ##STR28##           50,800                                                                            0.97                                                                             30.3                                                                             29.4                                                                             4.9                                    24                                                                                  ##STR29##           23,000                                                                            2.1                                                                              -- -- 8.0                                    __________________________________________________________________________

                  TABLE II                                                        ______________________________________                                                 C.sub.5 H.sub.6 /                                                             Catalyst                                                                      Precursor                                                            Example  Mole Ratio                                                                              FI.sup.a   Activity                                                                            BBF                                       ______________________________________                                        25       0         0.93        6,960                                                                              8.3                                       26       0.1       0.84       15,700                                                                              7.8                                       27       0.3       0.87       19,800                                                                              8.4                                       28       0.5       0.84       24,500                                                                              8.5                                       29       1.0       0.86       37,800                                                                              9.7                                       ______________________________________                                         .sup.a MI < 0.2.                                                         

                                      TABLE III                                   __________________________________________________________________________                         Cycloalkadiene/                                                               Catalyst Precursor                                       Example                                                                            Cycloalkadiene  Mole Ratio                                                                            Activity                                                                          FI BBF                                       __________________________________________________________________________    30   None            --      21,200                                                                            0.51                                                                             7.0                                       31                                                                                  ##STR30##      1:1     50,600                                                                            1.58                                                                             7.5                                       32                                                                                  ##STR31##      0.2:1   37,900                                                                            1.06                                                                             7.7                                       33                                                                                  ##STR32##      1:1     47,900                                                                            0.92                                                                             8.8                                       34                                                                                  ##STR33##      1:1     53,500                                                                            2.08                                                                             9.6                                       35                                                                                  ##STR34##      1:1     43,200                                                                            1.28                                                                             9.6                                       36                                                                                  ##STR35##      1:1     33,900                                                                            1.31                                                                             8.2                                       37                                                                                  ##STR36##      1:1     41,500                                                                            0.66                                                                             9.3                                       __________________________________________________________________________

                  TABLE IV                                                        ______________________________________                                                          Example                                                                       38   39                                                     ______________________________________                                        Cycloalkadiene/Catalyst                                                                           0      2.5                                                Precursor Mole Ratio                                                          MI                  20.7   4.07                                               FI                  570    96.1                                               MFR                 27.5   23.6                                               Zr (ppm)            4.9    2.1                                                BBF                 19.1   17.9                                               ______________________________________                                    

                                      TABLE V                                     __________________________________________________________________________                        Cycloalkadiene/Zr                                         Example                                                                            Cycloalkadiene Mole Ratio                                                                             Activity                                                                          MI FI MFR                                                                              BBF                                 __________________________________________________________________________    40                                                                                  ##STR37##     3.3      97000                                                                             0.60                                                                             13.1                                                                             22.0                                                                             --                                  41   "              3.3      49500                                                                             0.44                                                                             10.3                                                                             23.0                                                                             --                                  42                                                                                  ##STR38##     1.6      16000                                                                             0.27                                                                             5.36                                                                             19.7                                                                             --                                  43                                                                                  ##STR39##     3.6      38500                                                                             NF 5.65                                                                             --  6.8                                44   "              3.6      53900                                                                             1.72                                                                             50.1                                                                             29.0                                                                             17.4                                45                                                                                  ##STR40##     1.0      18300                                                                             0.46                                                                             14.4                                                                             31.0                                                                             --                                  46   "              1.0      50200                                                                             -- -- -- --                                  47                                                                                  ##STR41##     1.0      13200                                                                             -- -- -- --                                  48   None           --        4200                                                                             -- -- -- --                                  __________________________________________________________________________

                  TABLE VI                                                        ______________________________________                                                                H.sub.2,                                              Example C.sub.6.sup.= /C.sub.2.sup.=                                                          Al/Zr.sup.a                                                                           ppm  MI   MFR  Density                                                                             Activity                         ______________________________________                                        49      0.03    450     250   0.73                                                                              25   0.9211                                                                              4500                             50      0.032    350.sup.b                                                                            270   0.80                                                                              28   0.9190                                                                              3600                             51      0.028   600     210  0.9  17   0.9170                                                                              56,000                           52      0.027   650     245  1.2  17   0.9195                                                                              62,900                           53      0.027    600.sup.c                                                                            210  1.2  18   0.9194                                                                              30,000                           54      0.029   600     210  1.0  18   0.9180                                                                              43,400                           ______________________________________                                         .sup.a Nominal                                                                .sup.b 3.8 ppm Zr, Al/Zr  381                                                 .sup.c 0.97 ppm Zr; Al/Zr  260                                           

We claim:
 1. A catalyst composition comprising the reaction productof:a) a monocycloalkadienyl catalyst precursor having the formula:

    LMX.sub.X                                                  (I)

wherein: M is Ti, Zr, or Hf; L is a cycloalkadienyl ligand selected fromthe group consisting of cyclopentadienyl indenyl, and fluorenyloptionally substituted with one or more hydrocarbyl groups containing 1to 20 carbon atoms; each X is independently hydrogen, an aryl, alkyl,alkenyl, alkylaryl, or arylalkyl radical having 1-20 carbon atoms, ahydrocarboxy radical having 1-20 carbon atoms, a halide, a nitrogencontaining radical having 1-20 carbon atoms, or Q₂ YZ, wherein each Q isindependently selected from the group consisting of --O--, --NR--, --CR₂-- and --S--; Y is either C or S; and Z is selected from the groupconsisting of --OR, --NR₂, --CR₃, --SR, --SiR₃, --PR₂, --H, and arylgroups, with the proviso that when Q is --NR-- then Z is selected fromthe group consisting of --OR, --NR₂, --SR, --SiR₃, --PR₂ and --H; and xis 2, 3, or 4 depending upon the valence state of M; b) an activityenhancing cycloalkadiene; and c) an activating cocatalyst.
 2. A catalystcomposition comprising the reaction product of:a) a monocycloalkadienylcatalyst precursor having a formula selected from the group consistingof: ##STR42## wherein: M is Ti, Zr, or Hf; L is a cycloalkadienyl ligandselected from the group consisting of cyclopentadienyl, indenyl, andfluorenyl optionally substituted with one or more hydrocarbyl groupscontaining 1 to 20 carbon atoms; each Q is independently selected fromthe group consisting of --O--, --NR--, --CR₂ -- and --S--; Y is C or S;Z is selected from the group consisting of --OR, --NR₂, --CR₃, --SR,--SiR₃, --PR₂, --H, and aryl groups, with the proviso that when Q is--NR-- then Z is selected from the group consisting of --OR, --NR₂,--SR, --SiR₃, --PR₂, and --H; n is 1 or 2; A is a univalent anionicgroup when n is 2 or A is a divalent anionic group when n is 1; each Ris independently a group containing carbon, silicon, nitrogen, oxygen,and/or phosphorus, wherein one or more R groups may be attached to the Lsubstituent; T is a bridging group selected from the group consisting ofalkylene and arylene groups containing from 1 to 10 carbon atomsgermanium, silicone and alkyl phosphine; and m is 2 to 7; b) an activityenhancing cycloalkadiene; and c) an activating cocatalyst.
 3. Thecatalyst composition of claim 2, wherein the monocycloalkadienylcatalyst precursor is selected from the group consisting of indenylzirconium tris(diethylcarbamate), indenyl zirconiumtris(trimethylacetate), and (methylcyclopentadienyl) zirconiumtris(trimethylacetate).
 4. The catalyst composition of claim 1 or 2,wherein the activity enhancing cycloalkadiene is selected from the groupconsisting of cyclopentadiene, methylcyclopentadiene, indene, andmethyl-n-propylcyclopentadiene.
 5. The catalyst composition of claim 1or 2, wherein the activity enhancing cycloalkadiene is present in anamount of about 0.01 to about 10 moles per mole of catalyst precursor.6. The catalyst composition of claim 1 or 2, wherein the activatingcocatalyst is selected from the group consisting of methylaluminoxaneand modified methylaluminoxane.
 7. The catalyst composition of claim 1or 2 in liquid form.